Yes, convicts prefer 7.3ph , 24c and grow to 15cm. Angels prefer 7ph , 26c and grow to 15cm. HOWEVER !! this quote from Andy Cunningham (Age of Aquariums participent), " these fish are the axe wielding,homicidal maniacs of the tropical fish world..... and I love them. If they were dogs you would have to muzzle them and license them as a dangerous breed". In my opinion I think they could be kept together if you did not breed the convicts, they tend to stay low in the tank whereas the angels tend to be middle feeders.